PYSEC-2026-330
EPyT-Flow vulnerable to unsafe JSON deserialization (__type__)
Quick fix
PYSEC-2026-330 — epyt-flow: upgrade to the fixed version with the command below.
pip install --upgrade 'epyt-flow>=0.16.1'Details
### Impact EPyT-Flow’s REST API parses attacker-controlled JSON request bodies using a custom deserializer (my_load_from_json) that supports a __type__ field. When __type__ is present, the deserializer dynamically imports an attacker-specified module/class and instantiates it with attacker-supplied arguments. This allows invoking dangerous classes such as subprocess.Popen, which can lead to OS command execution during JSON parsing. This also affects the loading of JSON files.
### Patches EPyT-Flow has been patched in 0.16.1 -- affects all versions <= 0.16.0
### Workarounds Do not load any JSON from untrusted sources and do not expose the REST API.
### Credits EPyT-Flow thanks Jarrett Chan (@syphonetic) for detecting and reporting the bug.
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Affected packages
References
- https://github.com/WaterFutures/EPyT-Flow/security/advisories/GHSA-74vm-8frp-7w68[WEB]
- https://nvd.nist.gov/vuln/detail/CVE-2026-25632[ADVISORY]
- https://github.com/WaterFutures/EPyT-Flow/commit/3fff9151494c7dbc72073830b734f0a7e550e385[WEB]
- https://github.com/WaterFutures/EPyT-Flow[PACKAGE]
- https://github.com/WaterFutures/EPyT-Flow/releases/tag/v0.16.1[WEB]
- https://pypi.org/project/epyt-flow[PACKAGE]
- https://github.com/advisories/GHSA-74vm-8frp-7w68[ADVISORY]